[xaduha]

I never owned a yubikey and things probably changed over the years also since I last looked into it. But even so what you have there is a proprietary applet with lots of extensions https://developers.yubico.com/PIV/Introduction/Yubico_extens...

If it works with OpenSC out of the box, then that's because Yubico made it to work. I pretty sure that if you tried to use a publicly available PIV applet that does its PIV duties in accordance with the specs you are not going to have a good time trying to pair it with OpenSSH.

[knorker]

Well… do you still say that it's not particularly well suited, then?

If yes, then why?

[xaduha]

Decide for yourself, PIV is an old and sprawling monstrosity and if you go from the specs, then no, it's not particularly suited for this relatively simple task. Proprietary PIV applet made by Yubico might be, but is that a good thing? Not in my book when they easily could've done what Philip Wendland did there with IsoApplet, having several applets and switching between them is basic stuff.